package PTA2.ti55;

import java.util.Scanner;

/**
 * @author Lenovo
 */
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n =scanner.nextInt();
        if(n>26||n<1){
            System.out.println("error");
            return;
        }
        StringBuilder sb= new StringBuilder();
        for(int i=0;i<n;i++){
            char ch =(char) ('a'+i);
            sb.append(ch).append(" ");
        }
        for (int i=n-2;i>=0;i--){
            char ch =(char) ('a'+i);
            sb.append(ch).append(" ");
        }
        System.out.println(sb.toString());
    }
}
